- Cliché Storm: The biggest criticism of the film is that it relies too much on traditional horror clichés, such as Jump Scares and dream sequences, instead of properly building tension to provide scares. Some reviews even stated that the twist where Stephen is revealed to have been faking paralysis the whole time is easy to predict.
- Idiot Plot: If any of Stephen's doctors did their job and noticed that he's been faking his paralysis, the movie would have been over in the first ten minutes.
- Narm: The Reveal that Stephen somehow not only managed to fake his paralysis for six months, but managed to fool all of his doctors and Mary in faking said paralysis is so utterly ridiculous that it becomes unintentionally entertaining.
- Nightmare Retardant:
- The film tries to play a raccoon jumping out of a stack of wood for a scare, complete with Scare Chord... and fails miserably.
- While Stephen manages to come off as somewhat legitimately insane and scary, said scariness is rather undermined by the fact that his haircut bears an uncanny resemblance to Harry Osborn's similar haircut in The Amazing Spider-Man 2.
- Shocking Swerve:
- The reveal that Stephen is not really paralyzed, as that would mean he was somehow able to fake paralysis for several months without being found out at all by his doctors.
- Also, the reveal that he had been drugging Mary the whole time, which caused her odd dreams, as he was able to somehow move around the house and drug her without being noticed at all by her.
- Special Effect Failure: During the scene where Mary escapes from her restraints and throws up in the toilet while naked, it's pretty clear that a body double was used in that scene and not Naomi Watts, with how her face is not shown on camera for that sequence.
- They Copied It, So It Sucks!: The part in the final act where Dr. Wilson shows up at the house and gets killed by Stephen has been widely derided for blatantly ripping off The Shining.
- Took the Bad Film Seriously: Quite a few reviews have noted that the actors (particularly Naomi Watts) gave really good performances, but they were held back by the terrible screenplay.
YMMV / Shut In